Induction Of Nodules Research Articles

Induction and preliminary characterization of neoplastic pulmonary nodules in a transgenic pig model

ObjectivesLung cancer models in large animals are lacking. Oncopigs are transgenic pigs that carry both KRASG12D and TP53R167H Cre-inducible mutations. This study aimed to develop and histologically characterize a swine model of lung cancer that could serve for preclinical studies evaluating locoregional therapies. Materials and MethodsIn two Oncopigs, an adenoviral vector encoding the Cre-recombinase gene (AdCre) was injected endovascularly through the pulmonary arteries or inferior vena cava. In two other Oncopigs, a lung biopsy was performed and incubated with AdCre, before reinjecting the mixture into the lungs percutaneously. Animals were clinically and biologically (complete blood count, liver enzymes and lipasemia) monitored. Obtained tumors were characterized on computed tomography (CT) and on pathology and immunohistochemistry (IHC). ResultsNeoplastic lung nodules developed following 1 (1/10, 10%) endovascular inoculation, and 2 (2/6, 33%) percutaneous inoculations. All lung tumors were visible at the 1-week CT, and appeared as well-circumscribed solid nodules, with a median longest diameter of 14 mm (range: 5–27 mm). Only one complication occurred: an extravasation of the mixture into the thoracic wall during a percutaneous injection that resulted in a thoracic wall tumor. Pigs remained clinically healthy during the entire follow-up (14–21 days). On histology, tumors consisted of inflammatory undifferentiated neoplasms composed of atypical spindle and epithelioid cells and/or a fibrovascular stroma and abundant mixed leukocytic infiltrate. On IHC, atypical cells diffusely displayed expression of vimentin and some showed expression of CK WSS and CK 8/18. The tumor microenvironment contained abundant IBA1 + macrophages and giant cells, CD3 + T cells, and CD31 + blood vessels. ConclusionTumors induced in the lungs of Oncopigs are fast growing poorly differentiated neoplasms associated with a marked inflammatory reaction that can be easily and safely induced at site specific locations. This large animal model might be suitable for interventional and surgical therapies of lung cancer.

Paired Medicago receptors mediate broad-spectrum resistance to nodulation by Sinorhizobium meliloti carrying a species-specific gene

Plants have evolved the ability to distinguish between symbiotic and pathogenic microbial signals. However, potentially cooperative plant-microbe interactions often abort due to incompatible signaling. The Nodulation Specificity 1 (NS1) locus in the legume Medicago truncatula blocks tissue invasion and root nodule induction by many strains of the nitrogen-fixing symbiont Sinorhizobium meliloti. Controlling this strain-specific nodulation blockade are two genes at the NS1 locus, designated NS1a and NS1b, which encode malectin-like leucine-rich repeat receptor kinases. Expression of NS1a and NS1b is induced upon inoculation by both compatible and incompatible Sinorhizobium strains and is dependent on host perception of bacterial nodulation (Nod) factors. Both presence/absence and sequence polymorphisms of the paired receptors contribute to the evolution and functional diversification of the NS1 locus. A bacterial gene, designated rns1, is required for activation of NS1-mediated nodulation restriction. rns1 encodes a type I-secreted protein and is present in approximately 50% of the nearly 250 sequenced S. meliloti strains but not found in over 60 sequenced strains from the closely related species Sinorhizobium medicae. S. meliloti strains lacking functional rns1 are able to evade NS1-mediated nodulation blockade.

Live soil inocula, not host population or domestication status, is the predominant driver of growth benefits to cowpea

PurposeCrops rely on microbes for critical services, but host benefits can be influenced by local makeup of microbiota and the host’s capacity to select optimal strains. We investigated host benefits that cowpeas receive from microbiota depending on plant genotype, their domestication status, and soil source.MethodsWe performed a full factorial soil inoculation experiment. Twenty diverse cowpea genotypes, selected from wild and domesticated populations, were exposed to soil rinsates from four agricultural sites across California, all having cowpea cultivation and varied physicochemical features. Cowpea investment in and benefit from microbiota was quantified by measuring host growth response to inoculation, nodulation, and segregating trait variation.ResultsVariation in induction of root nodulation and strikingly heterogenous benefits to host growth were observed among soil sites. These effects were restricted to live soil inocula but were absent in autoclaved soil controls that lacked microbiota. Cowpeas expressed heritable variation in nodulation, but there was negligible effect of plant population or domestication status on the net benefit that hosts gained from microbiota.ConclusionSoils varied substantially and consistently among cultivation sites and were the most prominent driver shaping host growth effects on cowpeas. While growth benefits vary among host cultivars, soil microbiota (and the conditions that maintain them) predominantly shape plant performance in agricultural settings.

Histological and cytological study on meristematic nodule induction and shoot organogenesis in Paeonia ostii ‘Feng Dan’

This is the first report concerning the sequence of histological and cytological events occurring during organogenesis from cotyledon-derived meristematic nodules (MNs) in Paeonia ostii ‘Feng Dan’. Sections were made and studies were carried out with dissecting microscope, light microscope, scanning electron microscopy (SEM) and transmission electron microscopy observation. Histological studies revealed a complex developmental process of morphogenesis including five stages: (1) callus originated from cell division in both cambial and cortical regions; type I—yellow compact callus with densely arranged clumps was identified as embryogenic callus. (2) pre-nodular structure consisted of organization center (a central area of vascularization surrounded by meristematic cell layers) and an epidermis-like layer; (3) independent MNs comprised of organization center, a cortical-like area of parenchymatous cells and an epidermal-like area; (4) nodular clusters displayed vigorously internal meristematic cell division and generated a relative movement towards the nodules periphery, establishing vascular connection with primordia; (5) successive new elongated shoots with axillary bud primordia were developed. SEM observations showed three types of extracellular matrix, a smooth membranous layer, fibrillar structures and granular mucilage-like secretions on embryogenic callus, demonstrating its dynamic morphological changes. Ultrastructural analysis revealed striking changes of chloroplast morphology and starch content during MNs morphogenesis. This study allows a better understanding of in vitro regeneration via MN culture and provides references for protocol optimization and genetic transformation.

Chickpea shows genotype-specific nodulation responses across soil nitrogen environment and root disease resistance categories

BackgroundThe ability of chickpea to obtain sufficient nitrogen via its symbiotic relationship with Mesorhizobium ciceri is of critical importance in supporting growth and grain production. A number of factors can affect this symbiotic relationship including abiotic conditions, plant genotype, and disruptions to host signalling/perception networks. In order to support improved nodule formation in chickpea, we investigated how plant genotype and soil nutrient availability affect chickpea nodule formation and nitrogen fixation. Further, using transcriptomic profiling, we sought to identify gene expression patterns that characterize highly nodulated genotypes.ResultsA study involving six chickpea varieties demonstrated large genotype by soil nitrogen interaction effects on nodulation and further identified agronomic traits of genotypes (such as shoot weight) associated with high nodulation. We broadened our scope to consider 29 varieties and breeding lines to examine the relationship between soilborne disease resistance and the number of nodules developed and real-time nitrogen fixation. Results of this larger study supported the earlier genotype specific findings, however, disease resistance did not explain differences in nodulation across genotypes. Transcriptional profiling of six chickpea genotypes indicates that genes associated with signalling, N transport and cellular localization, as opposed to genes associated with the classical nodulation pathway, are more likely to predict whether a given genotype will exhibit high levels of nodule formation.ConclusionsThis research identified a number of key abiotic and genetic factors affecting chickpea nodule development and nitrogen fixation. These findings indicate that an improved understanding of genotype-specific factors affecting chickpea nodule induction and function are key research areas necessary to improving the benefits of rhizobial symbiosis in chickpea.

Mechanisms in plant growth-promoting rhizobacteria that enhance legume-rhizobial symbioses.

Nitrogen fixation is an important biological process in terrestrial ecosystems and for global crop production. Legume nodulation and N2 fixation have been improved using nodule-enhancing rhizobacteria (NER) under both regular and stressed conditions. The positive effect of NER on legume-rhizobia symbiosis can be facilitated by plant growth-promoting (PGP) mechanisms, some of which remain to be identified. NER that produce aminocyclopropane-1-carboxylic acid deaminase and indole acetic acid enhance the legume-rhizobia symbiosis through (i) enhancing the nodule induction, (ii) improving the competitiveness of rhizobia for nodulation, (iii) prolonging functional nodules by suppressing nodule senescence and (iv) upregulating genes associated with legume-rhizobia symbiosis. The means by which these processes enhance the legume-rhizobia symbiosis is the focus of this review. A better understanding of the mechanisms by which PGP rhizobacteria operate, and how they can be altered, will provide opportunities to enhance legume-rhizobial interactions, to provide new advances in plant growth promotion and N2 fixation.

Experimental evidence of mechanical lumpy skin disease virus transmission by Stomoxys calcitrans biting flies and Haematopota spp. horseflies

Lumpy skin disease (LSD) is a devastating disease of cattle characterized by fever, nodules on the skin, lymphadenopathy and milk drop. Several haematophagous arthropod species like dipterans and ticks are suspected to play a role in the transmission of LSDV. Few conclusive data are however available on the importance of biting flies and horseflies as potential vectors in LSDV transmission. Therefore an in vivo transmission study was carried out to investigate possible LSDV transmission by Stomoxys calcitrans biting flies and Haematopota spp. horseflies from experimentally infected viraemic donor bulls to acceptor bulls. LSDV transmission by Stomoxys calcitrans was evidenced in 3 independent experiments, LSDV transmission by Haematopota spp. was shown in one experiment. Evidence of LSD was supported by induction of nodules and virus detection in the blood of acceptor animals. Our results are supportive for a mechanical transmission of the virus by these vectors.

Appraising Endophyte–Plant Symbiosis for Improved Growth, Nodulation, Nitrogen Fixation and Abiotic Stress Tolerance: An Experimental Investigation with Chickpea (Cicer arietinum L.)

Chickpea is an important leguminous crop that improves soil fertility through atmospheric nitrogen fixation with the help of rhizobia present in nodules. Non-rhizobia endophytes are also capable of inducing nodulation and nitrogen fixation in leguminous crops. The aim of the current study was to isolate, characterize and identify the non-rhizobia endophytic bacterial strains from root nodules of chickpea. For this purpose, more than one hundred isolates were isolated from chickpea root nodules under aseptic conditions and were confirmed as endophytes through re-isolating them from root nodules of chickpea after their inoculation. Nineteen confirmed endophytic bacterial strains revealed significant production of indole acetic acid (IAA) both in presence and absence of L-tryptophan and showed their ability to grow under salt, pH and heavy metal stresses. These strains were evaluated for in vitro plant growth promoting (PGP) traits and results revealed that seven strains showed solubilization of P and colloidal chitin along with possessing catalase, oxidase, urease and chitinase activities. Seven P-solubilizing strains were further evaluated in a jar trial to explore their potential for promoting plant growth and induction of nodulation in chickpea roots. Two endophytic strains identified as Paenibacillus polymyxa ANM59 and Paenibacillus sp. ANM76 through partial sequencing of the 16S rRNA gene showed the maximum potential during in vitro PGP activities and improved plant growth and nodulation in chickpea under the jar trial. Use of these endophytic strains as a potential biofertilizer can help to reduce the dependence on chemical fertilizers while improving crop growth and soil health simultaneously.

Occurrence of diverse Bradyrhizobium spp. in roots and rhizospheres of two commercial Brazilian sugarcane cultivars.

The genus Bradyrhizobium harbors many endosymbionts of legumes, but recent research has shown their widespread presence in soils and in non-legumes, notably in roots of sugarcane. This study aimed to investigate the Bradyrhizobium sp. community density in the endosphere and the rhizosphere of two commercial sugarcane cultivars. Samples of the rhizosphere and root endosphere of two Brazilian sugarcane cultivars (RB867515 and IACSP95-5000) were collected, serially diluted, and inoculated on axenic cowpea (Vigna unguiculata) and the induction of nodules was evaluated. Based on the results, a density was estimated of at least 1.6 × 104 rhizobia g root-1 in rhizosphere samples and up to 105 rhizobia g root -1 in endosphere. BOX-PCR profiling of 93 Bradyrhizobium isolates revealed genetic variability, with some dominant (up to 18 representants) and less dominant genotypes. 16S rRNA and ITS sequence analyses confirmed nine phylotypes, six of which pertained to the B. elkanii clade and three to the B. japonicum clade. Five isolates were genetically similar to the recently described species B. sacchari. There was no effect of the factors "plant cultivar" and "root compartment" on Bradyrhizobium sp. community composition and the most abundant genotypes occurred both in rhizosphere and endosphere of both cultivars. Therefore, this study confirms the natural presence of diverse Bradyrhizobium spp. in sugarcane root systems (mainly the rhizosphere) and indicates that certain Bradyrhizobium phylotypes have a special affinity for sugarcane root colonization.

Role of fluorescent pseudomonas associated with root nodules of mungbean in the induction of nodulation by the rhizobia in mungbean.

Role of fluorescent pseudomonas associated with root nodules of mungbean in the induction of nodulation by the rhizobia in mungbean.

Two Rieske Fe/S Proteins and TAT System in Mesorhizobium loti MAFF303099: Differential Regulation and Roles on Nodulation.

Mesorhizobium loti MAFF303099 is a rhizobial strain that nodulates Lotus spp. A M. loti MAFF303099 mutant strain affected in the tatC gene was generated. This strain presented an altered protein secretion level to the culture supernatant and also a higher sensitivity to SDS. Its nodulation phenotype on Lotus showed the induction of small and colorless nodules, and in a larger number than those induced by the wild-type strain. In addition, these nodules presented defects in the degree of occupation by rhizobia. Two Rieske Fe/S proteins, encoded by the mll2707 and mlr0970 genes, were predicted as potential Tat substrates in M. loti MAFF303099. The transcriptional expression of mll2707 and mlr0970 genes was analyzed under different oxygen growth conditions. The mll2707 gene was expressed constitutively, while the expression of the mlr0970 gene was only detected under anaerobic and microaerophilic in vitro conditions. Both genes were down-regulated in the tatC mutant strain. mll2707 and mlr0970 mRNAs from the wild-type strain were detected in nodules. Using a translational reporter peptide fusion, we found that the Mll2707 protein was only detectable in the wild-type strain. On the other hand, although Mlr0970 protein was detected in wild-type and tatC mutant strains, its association with the membrane was favored in the wild-type strain. The tatC and the mll2707 mutant strains were affected in the cytochrome c oxidase activity. These results confirm that Mll2707 is required for cytochrome c-dependent respiration and that Tat functionality is required for the correct activity of Mll2707. The mll2707 mutant strain showed a nodulation phenotype similar to the tatC mutant strain, although it presented only a slight difference in comparison with wild-type strain in terms of nodule occupation. No defective phenotype was observed in the nodulation with the mlr0970 mutant strain. These results indicate that, of the two Rieske Fe/S proteins coded by M. loti MAFF303099, only Mll2707 expression is required for the induction of effective nodules, and that the functionality of the Tat system is necessary not only for the correct function of this protein, but also for some other protein required in an earlier stage of the nodulation process.

Mycorrhizal lipochitinoligosaccharides (LCOs) depolarize root hairs of Medicago truncatula.

Arbuscular Mycorrhiza and Root Nodule Symbiosis are symbiotic interactions with a high benefit for plant growth and crop production. Thus, it is of great interest to understand the developmental process of these symbioses in detail. We analysed very early symbiotic responses of Medicago truncatula root hair cells, by stimulation with lipochitinoligosaccharides specific for the induction of nodules (Nod-LCOs), or the interaction with mycorrhiza (Myc-LCOs). Intracellular micro electrodes were used, in combination with Ca2+ sensitive reporter dyes, to study the relations between cytosolic Ca2+ signals and membrane potential changes. We found that sulfated Myc- as well as Nod-LCOs initiate a membrane depolarization, which depends on the chemical composition of these signaling molecules, as well as the genotype of the plants that were studied. A successive application of sulfated Myc-LCOs and Nod-LCOs resulted only in a single transient depolarization, indicating that Myc-LCOs can repress plasma membrane responses to Nod-LCOs. In contrast to current models, the Nod-LCO-induced depolarization precedes changes in the cytosolic Ca2+ level of root hair cells. The Nod-LCO induced membrane depolarization thus is most likely independent of cytosolic Ca2+ signals and nuclear Ca2+ spiking.

Naturally occurring variations in the nod-independent model legume Aeschynomene evenia and relatives: a resource for nodulation genetics

BackgroundAmong semi-aquatic species of the legume genus Aeschynomene, some have the unique property of being root and stem-nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the production of Nod factors. These species provide an excellent biological system with which to explore the evolution of nodulation in legumes. Among them, Aeschynomene evenia has emerged as a model legume to undertake the genetic dissection of the so-called Nod-independent symbiosis. In addition to the genetic analysis of nodulation on a reference line, natural variation in a germplasm collection could also be surveyed to uncover genetic determinants of nodulation. To this aim, we investigated the patterns of genetic diversity in a collection of 226 Nod-independent Aeschynomene accessions.ResultsA combination of phylogenetic analyses, comprising ITS and low-copy nuclear genes, along with cytogenetic experiments and artificial hybridizations revealed the richness of the Nod-independent Aeschynomene group with the identification of 13 diploid and 6 polyploid well-differentiated taxa. A set of 54 SSRs was used to further delineate taxon boundaries and to identify different genotypes. Patterns of microsatellite diversity also illuminated the genetic basis of the Aeschynomene taxa that were all found to be predominantly autogamous and with a predicted simple disomic inheritance, two attributes favorable for genetics. In addition, taxa displaying a pronounced genetic diversity, notably A. evenia, A. indica and A. sensitiva, were characterized by a clear geographically-based genetic structure and variations in root and stem nodulation.ConclusionA well-characterized germplasm collection now exists as a major genetic resource to thoroughly explore the natural variation of nodulation in response to different bradyrhizobial strains. Symbiotic polymorphisms are expected to be found notably in the induction of nodulation, in nitrogen fixation and also in stem nodulation. Subsequent genetic analysis and locus mapping will pave the way for the identification of the underlying genes through forward or reverse genetics. Such discoveries will significantly contribute to our understanding of the molecular mechanisms underpinning how some Aeschynomene species can be efficiently nodulated in a Nod-independent fashion.

Allene oxide synthase, allene oxide cyclase and jasmonic acid levels in Lotus japonicus nodules.

Jasmonic acid (JA), its derivatives and its precursor cis-12-oxo phytodienoic acid (OPDA) form a group of phytohormones, the jasmonates, representing signal molecules involved in plant stress responses, in the defense against pathogens as well as in development. Elevated levels of JA have been shown to play a role in arbuscular mycorrhiza and in the induction of nitrogen-fixing root nodules. In this study, the gene families of two committed enzymes of the JA biosynthetic pathway, allene oxide synthase (AOS) and allene oxide cyclase (AOC), were characterized in the determinate nodule-forming model legume Lotus japonicus JA levels were to be analysed in the course of nodulation. Since in all L. japonicus organs examined, JA levels increased upon mechanical disturbance and wounding, an aeroponic culture system was established to allow for a quick harvest, followed by the analysis of JA levels in whole root and shoot systems. Nodulated plants were compared with non-nodulated plants grown on nitrate or ammonium as N source, respectively, over a five week-period. JA levels turned out to be more or less stable independently of the growth conditions. However, L. japonicus nodules formed on aeroponically grown plants often showed patches of cells with reduced bacteroid density, presumably a stress symptom. Immunolocalization using a heterologous antibody showed that the vascular systems of these nodules also seemed to contain less AOC protein than those of nodules of plants grown in perlite/vermiculite. Hence, aeroponically grown L. japonicus plants are likely to be habituated to stress which could have affected JA levels.

Expression in rice of an autoactive variant of Medicago truncatula DMI3, the Ca+2/calmodulin-dependent protein kinase from the common symbiotic pathway modifies root transcriptome and improves mycorrhizal colonization

Rice is the principle staple food for more than half of humankind. Frequently, productivity of rice is affected by low nitrogen in the soil and hence, for enhanced rice production it heavily relies on synthetic nitrogen fertilizers that beget economic and ecological costs. In this context, the interest in transferring legume-like biological nitrogen fixation capability to rice has increased lately. The rice-arbuscular mycorrhizal (AM) symbiosis is mediated by genes that are orthologous to legume-genes known to be essential constituents of the common symbiotic pathway (CSP) that facilitates the establishment of both rhizobial nitrogen fixation- and AM-symbioses in legumes. Particularly, DMI3 (Ca+2/calmodulin-dependent serine/threonine protein kinase, CCaMK), a component of the CSP, was found to play a paramount role in promoting the development of both types of symbioses. In fact, expression of autoactive version of DMI3 was shown to be sufficient to trigger downstream developmental processes leading to the induction of spontaneous nodulation in the absence of rhizobia. Hence, in the present investigation, we expressed in transgenic rice a gain-of-function Medicago truncatula DMI3 T271D gene (gofMtDMI3) and assessed if legume-like symbiotic responses can be mimicked in rice roots. Ectopic expression of gofMtDMI3 in common bean induced spontaneous nodulation in the roots in the absence of rhizobia, but in rice plants it did not produce any such legume-like nodular manifestations. Conversely, the expression of gofMtDMI3 supported elevated AM colonization in rice roots that could improve plant nutrition/growth. In addition, gofMtDMI3 expression induced higher transcript levels of the CSP orthologues OsDMI3, OsIPD3 and OsNSP1, as well as triggered changes in the expression of several genes involved in biotic and abiotic stress responses. Our results with gofMtDMI3 lay the basis for the potential development of a biotechnological approach towards improvement of rice production.

Symbiosis with Francisella tularensis provides resistance to pathogens in the silkworm

Francisella tularensis, the causative agent of tularemia, is a highly virulent facultative intracellular pathogen found in a wide range of animals, including arthropods, and environments. This bacterium has been known for over 100 years, but the lifestyle of F. tularensis in natural reservoirs remains largely unknown. Thus, we established a novel natural host model for F. tularensis using the silkworm (Bombyx mori), which is an insect model for infection by pathogens. F. tularensis established a symbiosis with silkworms, and bacteria were observed in the hemolymph. After infection with F. tularensis, the induction of melanization and nodulation, which are immune responses to bacterial infection, were inhibited in silkworms. Pre-inoculation of silkworms with F. tularensis enhanced the expression of antimicrobial peptides and resistance to infection by pathogenic bacteria. These results suggest that silkworms acquire host resistance via their symbiosis with F. tularensis, which may have important fitness benefits in natural reservoirs.

A Laser Dissection-RNAseq Analysis Highlights the Activation of Cytokinin Pathways by Nod Factors in the Medicago truncatula Root Epidermis.

Nod factors (NFs) are lipochitooligosaccharidic signal molecules produced by rhizobia, which play a key role in the rhizobium-legume symbiotic interaction. In this study, we analyzed the gene expression reprogramming induced by purified NF (4 and 24 h of treatment) in the root epidermis of the model legume Medicago truncatula Tissue-specific transcriptome analysis was achieved by laser-capture microdissection coupled to high-depth RNA sequencing. The expression of 17,191 genes was detected in the epidermis, among which 1,070 were found to be regulated by NF addition, including previously characterized NF-induced marker genes. Many genes exhibited strong levels of transcriptional activation, sometimes only transiently at 4 h, indicating highly dynamic regulation. Expression reprogramming affected a variety of cellular processes, including perception, signaling, regulation of gene expression, as well as cell wall, cytoskeleton, transport, metabolism, and defense, with numerous NF-induced genes never identified before. Strikingly, early epidermal activation of cytokinin (CK) pathways was indicated, based on the induction of CK metabolic and signaling genes, including the CRE1 receptor essential to promote nodulation. These transcriptional activations were independently validated using promoter:β-glucuronidase fusions with the MtCRE1 CK receptor gene and a CK response reporter (TWO COMPONENT SIGNALING SENSOR NEW). A CK pretreatment reduced the NF induction of the EARLY NODULIN11 (ENOD11) symbiotic marker, while a CK-degrading enzyme (CYTOKININ OXIDASE/DEHYDROGENASE3) ectopically expressed in the root epidermis led to increased NF induction of ENOD11 and nodulation. Therefore, CK may play both positive and negative roles in M. truncatula nodulation.

The pleiotropic effects of extract containing rhizobial Nod factors on pea growth and yield

AbstractRhizobial lipochitooligosacharides (Nod factors) influence the development of legume roots, including growth stimulation, nodule induction and root hair curling. However, their effect on the green parts of plants is less known, therefore we evaluated seed and foliar application of an extract containing Nod factors on pea growth and yield. Pea plants were examined from emergence to full maturity, including growth dynamics and morphological (nodule number and weight, the quantity and surface area of leaves) or physiological (photosynthesis and transpiration intensity, chlorophyll and nitrogen content) parameters. The foliar application Nod factor extract, or seed dressing followed by foliar application, resulted in the best outcomes. The number and weight of root nodules, the chlorophyll content in leaves, and the intensity of net photosynthesis were all elevated. As a consequence of Nod factor treatment, the dynamics of dry mass accumulation of pea organs were improved and the pod number was increased. A significant increase in pea yield was observed after Nod factor application. Increase of nodule and pod numbers and improved growth of roots appear to be amongst the beneficial effects of Nod factor extract on the activation of secondary plant meristems.

Induction of endometriotic nodules in an experimental baboon model mimicking human deep nodular lesions

To establish an experimental model for the study of deep nodular endometriosis. Induction of nodular endometriosis in baboons by grafting different uterine specimens to the peritoneal cavity. Research and university facilities. Ten baboons, to develop a model of induced deep nodular endometriosis. Biopsies of endometrium, and endometrium plus the junctional zone (JZ), full uterine thickness, and myometrium grafted to the peritoneum. Macroscopic descriptions recorded for observed induced lesions; staining with hematoxylin and eosin for histological evaluation and specific antibodies (CK22, CD10) for immunohistochemical studies; and analysis of surface area and volume of lesions, glandular density, and invasion of surrounding organs. The incidence of induced nodular endometriosis was 100%, but the extent depended on the tissue grafted. Lesions induced after grafting specimens containing the JZ were statistically significantly larger than those not containing the JZ. Surrounding organ invasion was reported in more than 40% of lesions after grafting specimens containing the JZ. The first experimental model of nodular endometriosis allows investigation of deeper nodular lesions as well as invasion phenomena associated with nodular lesions.

The diversity of actinorhizal symbiosis

Filamentous aerobic soil actinobacteria of the genus Frankia can induce the formation of nitrogen-fixing nodules on the roots of a diverse group of plants from eight dicotyledonous families, collectively called actinorhizal plants. Within nodules, Frankia can fix nitrogen while being hosted inside plant cells. Like in legume/rhizobia symbioses, bacteria can enter the plant root either intracellularly through an infection thread formed in a curled root hair, or intercellularly without root hair involvement, and the entry mechanism is determined by the host plant species. Nodule primordium formation is induced in the root pericycle as for lateral root primordia. Mature actinorhizal nodules are coralloid structures consisting of multiple lobes, each of which represents a modified lateral root without a root cap, a superficial periderm and with infected cells in the expanded cortex. In this review, an overview of nodule induction mechanisms and nodule structure is presented including comparisons with the corresponding mechanisms in legume symbioses.